Motion of the Hindfoot after Simulated Arthrodesis*

TLDR

No Other. Let's summarize. Background: "However, clinical estimates of these limitations are imprecise and motion of the individual joints cannot be specifically measured clinically." So: "Clinical estimates of motion limitations after hindfoot arthrodesis are imprecise, and individual joint motion cannot be measured clinically." Purpose: combine two purpose sentences: "It is important to be able to measure the limitation of motion of each joint after arthrodesis of the other joints in order to understand the clinical implication of the arthrodesis. Also, it is necessary to ascertain the effect of limiting the motion of these joints on the excursion of the posterior tibial tendon in order to determine when it is appropriate to reconstruct the tendon concomitantly with these arthrodeses." Summarize: "The study aims to quantify joint‑specific motion loss and posterior tibial tendon excursion after hindfoot arthrodesis to guide clinical decision‑making regarding tendon reconstruction." Mechanism: combine mechanism sentences: "Arthrodesis of the subtalar joint, triple arthrodesis, double arthrodesis, talonavicular, calcaneocuboid were simulated in a cadaver model, measuring range of motion of non‑fused joints with 3D magnetic tracking and posterior tibial tendon excursion." Summarize: "Using a cadaver model, the authors simulated various hindfoot arthrodeses and measured the range of motion of unfused joints and posterior tibial tendon excursion with a 3‑D magnetic tracking system." Findings: combine all findings: key results: talonavicular joint key; any arthrodesis including talonavicular limits motion to ~2 degrees and tendon excursion to 25%; calcaneocuboid arthrodesis little effect on subtalar, reduces talonavicular to 67% and retains 73% tendon excursion; subtalar arthrodesis retains 26% talonavicular, 56% calcaneocuboid, 46% tendon; talonavicular joint has greatest ROM and its arthrodesis eliminates motion of other joints; clinical relevance: arthrodesis of any triple joint complex limits motion of remaining joints.

Abstract

Arthrodesis of the subtalar joint, triple arthrodesis (involving the subtalar, talonavicular, and calcaneocuboid joints), double arthrodesis (involving the talonavicular and calcaneocuboid joints), arthrodesis of the talonavicular joint, and arthrodesis of the calcaneocuboid joint were simulated in a cadaver model, and the range of motion of each joint not involved in the simulated arthrodesis was measured with a three-dimensional magnetic space tracking system. The excursion of the posterior tibial tendon was also measured under all of these conditions. We found that any combination of simulated arthrodeses that included the talonavicular joint severely limited the motion of the remaining joints to about 2 degrees and limited the excursion of the posterior tibial tendon to 25 per cent of the preoperative value. Simulated arthrodesis of the calcaneocuboid joint had little effect on the range of motion of the subtalar joint, and it reduced the range of motion of the talonavicular joint to a mean of 67 per cent of the preoperative value; a mean of 73 per cent of the excursion of the posterior tibial tendon was retained. After simulated arthrodesis of the subtalar joint, a mean of 26 per cent of the motion of the talonavicular joint, 56 per cent of the motion of the calcaneocuboid joint, and 46 per cent of the excursion of the posterior tibial tendon was retained.The talonavicular joint is the key joint of the triple joint complex. The talonavicular joint had the greatest range of motion, and simulated arthrodesis of this joint essentially eliminated motion of the other joints of the complex.CLINICAL RELEVANCE: Arthrodesis of any of the joints of the so-called triple joint complex (the subtalar, talonavicular, and calcaneocuboid joints) limits the motion of the remaining, unfused joints. However, clinical estimates of these limitations are imprecise and motion of the individual joints cannot be specifically measured clinically. It is important to be able to measure the limitation of motion of each joint after arthrodesis of the other joints in order to understand the clinical implication of the arthrodesis. Also, it is necessary to ascertain the effect of limiting the motion of these joints on the excursion of the posterior tibial tendon in order to determine when it is appropriate to reconstruct the tendon concomitantly with these arthrodeses.